Microbiota Control Lung Th17 Cell Response and Plasticity Leading to Autoimmune Lung Disease

项目摘要。 肺部并发症是类风湿性关节炎(RA)患者常见且主要的死亡原因。 治疗方法是有限的，调节关节炎的药物实际上可以加重RA患者的肺部疾病，但几乎没有 已知与类风湿关节炎相关的肺部发病机制。很明显，肠道和肠道微生物群有很强的 在许多肺部疾病中都有影响。从机制上讲，这种被称为肠肺轴的现象是不好的。 已定义。我们报道，通过肠肺通讯，一种肠道共生的节段性丝状细菌 (SFB)能够扩增表达双T细胞受体(TCR)的辅助性T细胞17(Th17)细胞，导致肺 三级淋巴结构(TLS)，在自身免疫患者中，病变往往与预后不良有关。至 了解肠-肺轴，我们建议解决SFB促进Th17细胞的机制 反应、肠-肺迁移和肺TLS的形成。缺氧诱导因子-1α(HIF-1α)在 低氧组织，如肠道和炎症组织，已知可促进糖酵解和促进Th17细胞 差异化。最近的研究报道，组织培养箱中T细胞的复氧大大增强 HIF-1a诱导。重要的是，肠道(低氧)来源的T细胞进入肺(常氧)可能面临类似的氧气 改变。我们假设并将测试肠道微生物区系与肺复氧相结合是否- 调节肠源性肺CD_4~+T细胞缺氧诱导因子-1α的表达，促进其糖酵解活性和Th17细胞 承诺，以及不断恶化的肺部疾病。使用KikGR-光可转换模型追踪T细胞从肠道到 我们的新数据支持我们的假设，显示KikR(肠源性)的HIF-1α水平高于KikGCD4+ SFB+组小鼠肺内有T细胞，而脾内无T细胞。CCR6在Th17细胞中高表达。我们的新数据显示 2型肺泡上皮细胞(AEC2)在自身免疫前产生丰富的CCL20，CCR6配体 疾病阶段。我们将测试AEC2的CCL20是否需要肺微生物区系和先天信号 利用AEC2特异性MyD88和CCL20缺失表达和Th17细胞募集。最近，Gut 已经证明，微生物群局部诱导了一种有趣的肠道T细胞型共表达RoRγt+和foxp3+， 掌握Th17细胞和Tregs的调节。然而，肠道微生物区系是否以及如何远程调节T 肺内细胞的可塑性仍不清楚。我们的新数据显示，一个独特的IL-17+Foxp3+细胞群体 与sFb−小鼠相比，sFb+组小鼠肺组织中DNA含量显著增加。我们将通过Treg Fate检测T细胞的可塑性 作图，并使用单细胞TCR分析来分析微生物群倾斜的双TCR谱系是否允许 Foxp3+T细胞获得Th17样表型。最后，我们将使用CRE-loxP系统来解决 IL-17+Foxp3+T细胞在肺自身免疫中的“恶”作用。通过采取一种独特的方法追踪肠道-肺 相声，这项建议允许研究揭示肠肺轴的病因，有助于为 设计未来的治疗方法来对抗肠-肺轴相关疾病。

Project Summary. Lung complications are a common and major cause of death in patients with rheumatoid arthritis (RA). Therapies are limited, and arthritis modulating drugs can actually worsen lung disease in RA patients, yet little is known regarding RA-related lung pathogenesis. It is evident that the gut and gut microbiota have a strong influence in many lung diseases. Mechanistically, this phenomenon known as the gut-lung axis, is poorly defined. We reported that through gut-lung communication, a gut commensal, segmented filamentous bacteria (SFB) are able to expand dual T cell receptor (TCR)-expressing T helper 17 (Th17) cells, leading to lung tertiary lymphoid structures (TLS), lesions often associated with poor prognosis in autoimmune patients. To understand gut-lung axis, we propose addressing the mechanisms utilized by SFB to promote a Th17 cell response, gut-lung migration, and lung TLS formation. Hypoxia-inducible factor-1α (HIF-1α) senses O2 in hypoxic tissues, e.g. the gut and inflamed tissues, and is known to enhance glycolysis and promote Th17 cell differentiation. Recent studies reported reoxygenation of T cells in tissue culture chambers greatly enhances HIF-1a induction. Importantly, gut (hypoxic)-derived T cells entering the lung (normoxic) may face similar O2 changes. We hypothesize and will test whether the gut microbiota in combination with lung reoxygenation up- regulate HIF-1α expression in gut-derived lung CD4+ T cells, promoting their glycolytic activity and Th17 cell commitment, and worsening lung disease. Using the KikGR-photoconvertible model to trace T cells from gut to lung, our new data favor our hypothesis by showing a higher HIF-1α level in KikR (gut-derived) than KikG CD4+ T cells in lung but not spleen of SFB+ mice. CCR6 is highly expressed by Th17 cells. Our new data show that type 2 alveolar epithelial cells (AEC2) produce abundant CCL20, the CCR6 ligand in the pre-autoimmune disease phase. We will test whether lung microbiota and innate signaling are required for AEC2s’ CCL20 expression and Th17 cell recruitment by using AEC2-specific MyD88 and CCL20 depletions. Recently, gut microbiota have been shown to locally induce an intriguing gut T cell type co-expressing Rorγt+ and Foxp3+, master regulators of Th17 cells and Tregs. However, whether and how gut microbiota can remotely regulate T cell plasticity in the lung remains unknown. Our new data show that a unique population of IL-17+Foxp3+ cells is significantly increased in lung of SFB+ over SFB− mice. We will examine T cell plasticity by Treg fate mapping, and use single cell TCR analysis to analyze whether a microbiota-skewed dual TCR repertoire allows Foxp3+ T cells to acquire a Th17-like phenotype. Finally, we will use the Cre-loxP system to address the “good or evil” function of IL-17+Foxp3+ T cells in lung autoimmunity. By taking a unique approach of tracking gut-lung crosstalk, this proposal permits studies to reveal the etiology of gut-lung axis, helping to pave the way for the designing of future therapies to combat gut-lung axis-related diseases.